They may look like a rough-and-ready crowd, but the bikers heading into Thunder on the Rock in Monteagle, Tenn., this weekend are also a bunch of softies. At least that's the word from spokeswoman Andrea Gilliam, who says she's been impressed by their giving spirit since she signed on four years ago.

"They've all won my heart over," said Gilliam.

Some 6,500 rowdies are expected for this fifth annual edition of Thunder on the Rock, a motorcycle rally and musical festival that has booked acts ranging from a Kiss tribute band to country artists to Southern rockers.

Even with its adults-only age restrictions and the rumbling backbeat of V-twin engines, the overall vibe of the festival is fairly laid-back, said Gilliam, comparing it to another Tennessee summer festival.

"We treat it a lot like Bonnaroo," she said. "A lot of people plan their vacations around us."

New this year is a Battle of the Bands to crown a "King of the Rock." Twenty regional acts are in contention for the honor, which includes a cash prize, an opening gig for Sunday's headliners and a guaranteed slot as a featured band at next year's festival.

Music starts at 2 p.m. today, with Molly Hatchet headlining at 10 p.m. (all times are Central).

Saturday opens with a Veterans Memorial Ride at 9:30 a.m. through the city of Monteagle. The parade is held in honor of Memorial Day and is open to any biker, not just those attending Thunder on the Rock.

The Thunder crowd will then head back to the venue for the bike show, bike games and more music. Saturday's featured acts are Big Engine, Georgia Satellites and The Fabulous Thunderbirds.

Sunday's schedule offers more bike games and music by the top three finishers in the Battle of the Bands, followed by country acts Leah Seawright and Mustang Sally. Then the crowd can "Rock and Roll All Nite" with the tribute band Kiss Army.

When all is said and done this weekend, Gilliam said she expects event organizers can offer considerable help to three charities.

Two were part of the initial plans for the festival. Proceeds from a dunking booth are earmarked for the American Cancer Society, and Erlanger Children's Hospital in Chattanooga will receive donated toys and games.

The third need became apparent after the devastating tornadoes of April 27. To help prolong the relief effort for victims of the storm in Tennessee, Georgia and Alabama, festival organizers will donate $1 from each ticket sold.

"At first we all put our time and money and effort into making sure everything's OK, but then that help sometimes falls and the needs are still there," Gilliam said. "This was something we wanted to do, now that a little time has passed, to give back to our community."